Expanding our understanding of the global impact of physical inactivity
Authors: Peter T Katzmarzyk
Journal: The Lancet Global Health (2022)

Physical inactivity (ie, not meeting WHO recommendations for physical activity) is a highly prevalent risk factor for premature mortality and several non-communicable diseases (NCDs).1Lee IM Shiroma EJ Lobelo F Puska P Blair SN Katzmarzyk PT Effect of physical inactivity on major non-communicable diseases worldwide: an analysis of burden of disease and life expectancy.Lancet. 2012; 380: 219-229Summary Full Text Full Text PDF PubMed Scopus (5382) Google Scholar An important metric of public health burden is health-care cost; physical inactivity cost health-care systems INT$53·8 billion worldwide in 2013.2Ding D Lawson KD Kolbe-Alexander TL et al.The economic burden of physical inactivity: a global analysis of major non-communicable diseases.Lancet. 2016; 388: 1311-1324Summary Full Text Full Text PDF PubMed Scopus (1206) Google Scholar The scientific evidence base on the health effects and global burden of physical inactivity has expanded greatly.32018 Physical Activity Guidelines Advisory Committee2018 Physical Activity Guidelines Advisory Committee scientific report. US Department of Health and Human Services, Washington, DC2018Google Scholar, 4Bull FC Al-Ansari SS Biddle S et al.World Health Organization 2020 guidelines on physical activity and sedentary behaviour.Br J Sports Med. 2020; 54: 1451-1462Crossref PubMed Scopus (2958) Google Scholar, 5Katzmarzyk PT Friedenreich C Shiroma EJ Lee IM Physical inactivity and non-communicable disease burden in low-income, middle-income and high-income countries.Br J Sports Med. 2022; 56: 101-106Crossref PubMed Scopus (141) Google Scholar Despite these scientific advances, the global prevalence of physical inactivity among adults was 27·5% in 2016, an estimate that remained stable since 2001.6Guthold R Stevens GA Riley LM Bull FC Worldwide trends in insufficient physical activity from 2001 to 2016: a pooled analysis of 358 population-based surveys with 1·9 million participants.Lancet Glob Health. 2018; 6: e1077-e1086Summary Full Text Full Text PDF PubMed Scopus (2224) Google Scholar In The Lancet Global Health, Andreia Costa Santos and colleagues7Costa Santos A Willumsen J Meheus F Ilbawi A Bull FC The cost of inaction on physical inactivity to public health-care systems: a population-attributable fraction analysis.Lancet Glob Health. 2022; (published online Dec 5.)https://doi.org/10.1016/S2214-109X(22)00464-8Google Scholar present new data on the global economic costs of physical inactivity. The authors report that, in the absence of any change in the global prevalence of physical inactivity, almost 500 million new cases of preventable NCDs and INT$520 billion in associated health-care costs would be realised between 2020 and 2030 (11 years). The authors have modelled these estimates using a population attributable fraction (PAF) approach that combines estimates of prevalence (of physical inactivity) and the associated relative risk of several NCDs (outcomes) from the literature. They then applied the PAF estimates to derive the attributable health-care costs, based on estimates of future, preventable cases. Earlier studies1Lee IM Shiroma EJ Lobelo F Puska P Blair SN Katzmarzyk PT Effect of physical inactivity on major non-communicable diseases worldwide: an analysis of burden of disease and life expectancy.Lancet. 2012; 380: 219-229Summary Full Text Full Text PDF PubMed Scopus (5382) Google Scholar, 2Ding D Lawson KD Kolbe-Alexander TL et al.The economic burden of physical inactivity: a global analysis of major non-communicable diseases.Lancet. 2016; 388: 1311-1324Summary Full Text Full Text PDF PubMed Scopus (1206) Google Scholar of the global health burden of physical inactivity have used similar PAF approaches to derive prevalence-based estimates of burden and cost, using a conservative approach that was based on health outcomes with strong associations with physical inactivity.8Physical Activity Guidelines Advisory CommitteePhysical Activity Guidelines Advisory Committee Report, 2008. US Department of Health and Human Services, Washington, DC2008Google Scholar Over the past couple of decades, there has been a great increase in research on the health effects of physical inactivity, and the list of NCDs that are strongly related to physical inactivity has expanded considerably.32018 Physical Activity Guidelines Advisory Committee2018 Physical Activity Guidelines Advisory Committee scientific report. US Department of Health and Human Services, Washington, DC2018Google Scholar The data presented by Costa Santos and colleagues are novel in that they include several new or updated PAFs for physical inactivity and NCDs, including coronary heart disease, stroke, type 2 diabetes, several cancers (breast, colon, bladder, endometrial, gastric, oesophageal, and renal), and mental health conditions (depression and dementia).5Katzmarzyk PT Friedenreich C Shiroma EJ Lee IM Physical inactivity and non-communicable disease burden in low-income, middle-income and high-income countries.Br J Sports Med. 2022; 56: 101-106Crossref PubMed Scopus (141) Google Scholar Another major advance is the focus on future health-care costs rather than prevalent costs, which highlights the potential of physical activity to significantly reduce rising health-care costs. The results reported by Costa Santos and colleagues7Costa Santos A Willumsen J Meheus F Ilbawi A Bull FC The cost of inaction on physical inactivity to public health-care systems: a population-attributable fraction analysis.Lancet Glob Health. 2022; (published online Dec 5.)https://doi.org/10.1016/S2214-109X(22)00464-8Google Scholar show the potential of physical activity to positively affect the global burden of NCDs. However, the results represent only a small proportion of the total societal burden of physical inactivity. For example, indirect economic costs (eg, those costs associated with absenteeism, presenteeism, or lost productivity due to premature mortality) were not addressed in this analysis, and these costs are often substantial.2Ding D Lawson KD Kolbe-Alexander TL et al.The economic burden of physical inactivity: a global analysis of major non-communicable diseases.Lancet. 2016; 388: 1311-1324Summary Full Text Full Text PDF PubMed Scopus (1206) Google Scholar Further, the analysis used a dichotomous exposure related to physical inactivity (active vs inactive); given that the association between physical inactivity and several NCDs follows a curvilinear dose-response association, computation of PAFs using multiple levels of physical inactivity might further refine the estimates. Also, the PAFs were limited to NCDs that have shown strong associations with physical inactivity; there are a host of additional NCDs that show moderate or limited associations with physical inactivity. For these reasons, the results presented by Costa Santos and colleagues should be considered conservative. Future research should be directed at clarifying these associations and addressing these analytical issues for their inclusion in future analyses. The evidence indicates that physical inactivity is a major NCD risk factor that carries a considerable public health burden. This issue is of global concern; the absolute NCD mortality burden attributable to physical inactivity is greatest in middle-income countries, where the bulk of the world's population lives.5Katzmarzyk PT Friedenreich C Shiroma EJ Lee IM Physical inactivity and non-communicable disease burden in low-income, middle-income and high-income countries.Br J Sports Med. 2022; 56: 101-106Crossref PubMed Scopus (141) Google Scholar However, the highest projected health-care costs are in high-income countries.7Costa Santos A Willumsen J Meheus F Ilbawi A Bull FC The cost of inaction on physical inactivity to public health-care systems: a population-attributable fraction analysis.Lancet Glob Health. 2022; (published online Dec 5.)https://doi.org/10.1016/S2214-109X(22)00464-8Google Scholar Concerted actions and policies are required if the WHO Global Action Plan on Physical Activity (GAPPA) 2018–30 goal of a relative 15% reduction in physical inactivity by 2030 is to be realised.9WHOGlobal action plan on physical activity 2018–30: more active people for a healthier world. World Health Organization, Geneva2018Google Scholar The GAPPA provides valuable resources and policy recommendations for increasing physical activity and improving health at multiple levels. In times of fiscal scarcity, the results presented by Costa Santos and colleagues, together with guidance from the GAPPA, highlight the potential substantial return of investment from the promotion of physical activity. I declare no competing interests. The cost of inaction on physical inactivity to public health-care systems: a population-attributable fraction analysisThis health and economic burden of physical inactivity is avoidable. Further investments in and implementation of known and effective policy interventions will support countries to reach the Sustainable Development Goal of reduction of NCD mortality by 2030. Full-Text PDF Open Access